Adjustable screen



LL CARETTO.

Y ADJUSTABLE SCREEN. APPLICATION F|LDJuNE1s,1921.

Patented June 6,1922.

UIT-Eu stares ATENT QFFlQiF.. i

LOUIS GABETTI), 02E BALDWIN, NEW YORK.

.ADJUSTABLE SCREEN.

Specification of Letters Patent.

Patented June 6; 1922.

'Application filed June is, 1921. semi No. 478,482.

grades or sizes of material with the same screen.

A further object includes the provision of an 'adjustable screen which is simple, yet rugged, in construction and which is reliable and efficient in operation. A still further object includes the provision of a shiftable l grading device which is constructed to coact with fixed grading means to thereby obtain varying meshes for different grades of materials.

Other objects will appear hereinafter from the specification and claims.

I obtain these objects by the device illustrated inthe appending drawing of whichr Fig. 1 is a plan view;

Fig. 2 is a view of a portion of the fixed grading means and the movable grading device;

Fig. 3 is a cross sectional viewtaken on lines 3 3 of Fig. 1, looking in the direction of the arrows; j

Fig. 4 is. in part. a similar view as Fig. 3. but showing a different relation of the screen rods;

Fig. 5 is a longitudinal section on lines 5-5 of Fig. 3.

Similar numerals refer to similar parts throughout the several views. For the purposeJ of illustration, I have shown my device as comprising a base or main supporting frame 6, havingsides 7, an upper closed end 8 and bottom pieces 9. This frame or supporting base may be made of any suitable material, as wood, metal. etc., and it may assume any desired and suitable shape. In my construction I prefer a substantially bottomless box with the top and one end open for the purpose hereinafter stated.

On the sides of this support. or frame, there are secured, by any convenient means. as nails or screws 10. the fixed grading means or screen bar sections 11. These sections are interchangeable and comprise suitable straps 12 having securely fastened or welded thereto screen rods 13.

Immediately beneath the lined screen bar sections is the adjustable or movable grading device for regulating and determiningv the size of the material. This device consists of a skeleton structure, or frame, and screen bars. The skeleton structure iscomposed of a number of spacer bars 16,- which are securely held by tie bars 17 at either end. The spacer bars 16 are provided with holes 18 for receiving and holdingthe movable screen rods la in position. These rods are, preferably. of the length of the opening in the bottom of the frame and constitute the grading means due to the relative position with relation to the lined bars, which these movable bars take by being shifted laterally with the skeleton frame. rllhe spacer bars 16 extend through slots 19, in the sides of the main frame. Across two or more of these slots on each'side 7 there are fastened holding and adjusting plates 20, having thumb screws 21 or equivalent device for the purpose stated below. To protect the movable skeleton or frame,vside pieces 22 may be provided, if desired. j l l It is obvious that, to`obtain the greatest screening range, the screen rods are spaced equally distant on the respective supporting straps 12 andthe spacer bars 16 and that the distance between the respective bars determines the larger size of material obtained. If it is desired. thereforeT to obtain fine screening materials. as plaster sand, it is only necessary to adjust the movable skeleton frame so that screen bars 14 are substantially midway between the lined bars 13 as illustrated for example in Figs. 2 and 4.

vIf larger sized material is desired the adjustable frame is moved laterally t-he desired distance, and the largest sizes of material are obtained when the screen lrods assume the relative position best illustrated in Fig. 3 (and Fig. 1). Intermediate grades of materials are obtained. of course. by having the movable screen bars take any desired position between the extremes stated above. It will benoted that the thumb screws hold 'the movable frame in position and that the adjustment may be quickly made.

By my adjustable screen, therefore, I am enabled to obtain graded materials by the adjustment herein described and it will not be necessary to purchase and maintain several screens Yfor obtaining different sized material. I find by actual use that my deas obvious modifications coming within the scope and spirit of my invention will suggest themselves to those skilled in the art.

l/Vhat I claim, therefore, as new and useful, and of my own invention, and desire to secure by Letters Patent, is

1. In a sand and gravel screen, a supporting frame having vertical side walls with slots therein, sections of fixed bars attached on said walls, and means movable laterally through said slots in the walls of said frame for varying the effective spacesbetween t-he bars of said sections.

2. The combination, in an adjustable sand and gravel screen, of a main frame and an auxiliary frame, screen bars on said frames, means on said main frame for protecting said auxiliary frame and means for adjusting theoperative` distances between said bars.

3. In an adjustable sand and gravel screen, a main frame having sides and Vprovided with a rectangular opening, sections of parallel screen bars attached to the sides of the main frame and across said opening, slots in the sides of the main frame, spacer bars projecting through said slots, connecting bars for the ends of said spacer bars to form a rigid frame, thumb screws for holding the rigid frame in different posit-ions,

and screen rods carried by said spacer bars.k

4. The combination, in an adjustable screen, with vertical side walls, of 'sections of fixed screen bars carried by said walls,

movable screen bars cooperating laterally.

lfor varying the effective lopenings between said bars.

6. An adjustable sand and gravel screen, comprising'l side walls vertically aiira' ed and spaced apart, pairs vof holding st fastened` onto said side walls, ,screen4 bars fastened in spaced relation to each pair? of ,Y

said strapsto form fixed screen sections, aA

plurality of movable transverse bars extending vthrough slotsin said side wall, and holding parallel. spaced bars for cooperating `with said fixed bars to vary the effective distance between said bars.. p n

In testimony whereof I have hereunto set my hand on this lQth day` of May, A. D., 1921. l, y I vLOUIS 'CARETTQ n 

